Vaisala K-PATENTS PR-23 Series, Instruction Manual, Page: 146 / 246

136 PR-23 instruction manual
9.10.2 Installation
Sensor wiring must follow drawing WRG-367 or WRG-350, see Figure 9.33 on next
page. See also Figure 4.5 on page 22 and Figure 4.8 on page 25.
Important: The FM unit installations must comply with the relevant requirements
of National Electrical Code (ANSI/NFPA 70) for Division 2 Hazardous (Classified) Lo-
cations and all instructions in this manual.
All wiring of PR-23-...-FM systems must
run in a conduit.
Important: Tampering and replacement with other than original Vaisala
K-PATENTS® components is not allowed because this may affect adversely the
safe use of the system.
Note: Sensor connector shall not be connected or disconnected when the circuits are
energized. Switch OFF the power from Indicating transmitter DTR external power
switch before disconnecting sensor cable from sensor. After connecting sensor cable
back to the sensor you can switch power on again.
Important: Provisions shall be made to prevent the rated voltage from being ex-
ceeded by transient disturbances of more than 119V.
Important: The refractometer models PR-23-M, PR-23-MS and PR-23-W contain
parts made of PTFE in sensor heads. These parts are subject to electrostatic haz-
ard. The refractometer models PR-23-M, PR-23-MS and PR-23-W shall only be used
for measuring liquids with high conductivity (> 10000 pS/m) in the presence of haz-
ardous atmospheres.
Important: The painted surface of the enclosure of PR-23-MS refractometer is sub-
ject to electrostatic hazard and therefore the cleaning shall be done only with a damp
cloth in the presence of hazardous atmospheres.